Screen clearer for gyratory sifters



EFHw. 21, 11950 H. H. MOYER SCREEN CLEARER FOR GYRATORY SIFTERS Filed Dec. 6, 1945 2 Sheets-Sheet 1 /0 J9 149.1. 73 If INVENTOR mo m/ A'I'FORNEYS Fm 21, 1950 H. H. MOYER 2,497,902

SCREEN CLEARER FOR GYRATORY SIFTERS Filed Dec. 6, 1945 2 Sheets-Sheet 2 13 m 2046 l gm 6 9' 14 z s 2 w 7 2/ 7 "1380 ,2

BY j 7 M04 W ATTORNEYS Patented Feb. 21, 1950 UNITED S A ES PATENT oF cE;

HowardH. Moyer, Lockport, N. Y., assignor to Richmond Manufacturing Cornpany, iloc kport, N; Y., a corporation of New York Application December .6, 1945, Serial 1810.63.3 29! This invention relates to'a screen for gyrating sifters, screens or bolting equipment and more particularly to such a screen which works in conjunction withloosely supported screen cleaner s such screen cleaners bouncing and moving erratically below the surface of the screening cloth andserving to keep the meshes of the sifting, screening or bolting silks, wires or other sc 'eening elements from clogging with the material being separated or graded. The invention is particularly applicable to high speed gyrating sitters, that is, sifters describing from one and one-half to three inch circles atfa speed of from 250 to 300 R. P. M. as compared with earlier low speed gyrating Sifters operating at approximately 180 R. P. M. and describing a larger circle in the order of four inches in diameter. The high speed sifter has a remarkable bolting or sifting action but with certain stocks, such as sulfur, has not proved to be advantageous due to the lack of an adequate cleaner medium. The present invention is directed to the eflicient cleaning of the screening cloth to achievethe advantage of high speed gyratory sifting with materials which tend to blind the cloth, although the invention is not, of course,'limited in its use to a high speed siiter nor to any type of stock and in particular can be used advantageously in bolting such materials as wheat flour in which use the capacity or the screen is greatly increased.

Thisapplication is a companion to the copend ing application for patent of Percy Pickard, Serial No. 774.368. filed September 16, 1947', now Patent No. 2,455,383, December 7, 1948, and to my application Serial No. 633,203, filed December 6, 1945, both for screen for'gyrating shake sifters.

Screens for gyrating sifters or bolting equiprnent are usually arranged in a stack and each screen of the stack is usually in the form of a rectangular wooden frame which may be divided by central wooden cross pieces into rectangular sections and over which is stretched the sifting, beltin or screening cloth of silk, wire cloth or the like which effects the separation of the material being graded. Below this sifting screening or bolting cloth is usually arranged a cleaner carrier usually the form of a grate of coarsely woven wires and on which they screen cleaners are loosely supported. These screen cleaners Below the such la 5 Claims. (Cl. 209 3 81) 2 V proper channels orways provided at the sides of h 133 I me H eWI th use i 1 metal p a o t i .sh rs r s .spt sns ltlie spaces between the screens in the stack often being left open so that the product from one screen drops onto the next lower screen and is not ca ried out on such interposed metal plate. It has been found that with rnat erials which are difficult to sift, such as sulfur, the capacity of the sitter is greatly increased if the activity of the'screen cleaners is increased and inparticular if the activity of thescreen cleaners'is extended uniformly to the corners and extremities of the screen n cl i o p it n to th normal i d n v o he ree slean s t s sss e h ir a ion in t e en er. t sc e n n clo i h t n e y n t n permit excessi l n s the'c'orners and extremities of the screening cloth ut a ss es lts. exce s W a n t center of the screening cloth. It has also been found ithstt s ca acit fth s t r is ea n r a AI s s. inusd arrin of th sc een is fi sd g eing eff cti th. with b n silks and un'stretc hable wire cloth to prevent the s e n m ssi It is accordingly the principal object of the present. inv ntin to r vide a r n f a 'rating shake slfter inwhich the mesh of the screening cloth is prevented from blinding thereby to permit of sifting such materials as sulfur and to increase the overall efiiciency and capacity of the t ess th. n ma mat als- Another object of the invention is to provide such ascreen which the activity of each screen cleaner is increased and in which the tendency of cl ane to rem i at the cen er of tb ssmrsrtrls it whi h i i n mall squnn i restra ed. and i whi h n p ticu a h. s re n cleaner isle i ra i ac i an is .i rswietq n can Qf t e sr n so es i i l 0. a p ts c the sc enin loth. thereb t c eas he q sifall s i ienq and a ac ty 9 th ssrssnin slsths l as ts sec fo w a thereof.

Arethsrphis t stil s n s i q s W r such a ssa'mssas f r arr n the nin slqth Whi e fies ra has th fib and ms cribs to mat rial n a th ins pe ci y f the s reen n l h nd t rig materials which are difiicult to is s ren bei ef ec e b h .55

rc neiieii iqfsrss 9ers al y em -bye i a screen frame and which very materially reduce the effective face area of the screening cloth.

It is a further object to provide a screen in which this jarring action is derived from the erratic movement of the screen cleaners.

Another object is to provide such a screen in which there is minimum wear, particularly of the screening cloth.

Another object is to provide such a screen in which the permitted movement of each screen cleaner is reduced to secure increased activity of the screen cleaners.

Another important object is to support the screening cloth in such manner that it is prevented from sagging when it becomes stretched or when a heavy load is placed upon the same and at the same time does not cut or wear the screening cloth.

Another object is to provide such a screen in which the means for reducing the permitted movement of each screen cleaner is a part of the structure for so supporting .and jarring the screening cloth and thereby is acted upon by all of the screen cleaners for a screen frame.

Another object is to provide such a structure for supporting and jarring the screen cloth which can be made to act upon the screening cloth at a plurality of places.

Another object is to provide such a screen in which a lighter grade of woven wire can be used for the cleaner carrier and in particular in which low cost standard galvanized hardware mesh can be employed.

Another object is to provide such a screen which is simple and inexpensive in construction and which will stand up under conditions of severe and constant use without getting out of order or requiring repairs.

Other objects and advantages will appear from the following description and drawings, in which:

Fig. 1 is a top plan view of the inner frame of a screen embodying the present invention and showing a part of the screening cloth broken away.

Fig. 2 is a vertical section, taken on line 2-2, Fig. 1.

Fig. 3 is an enlarged, horizontal, fragmentary view taken on line 3-3, Fig. 2.

Fig. 4 is an enlarged, vertical, fragmentary section taken on line I-l, Fig. 1.

Fig. 5 is a view similar to Fig. 1 of a modified form of the invention and showing the screening cloth removed.

Fig. 6 is a vertical section taken on line 6-6, Fig. 5.

In Figs. 14 is illustrated the inner frame 0 one unit or screen for sifting, bolting, separating, screening or grading material into different sizes,

such screens or units being usually piled one on top of the other to form a stack and the stack of such screens or units being arranged in a gyrating machine so that a gyrating action is imparted'to the stack, usually in a generally horizontal direction. I

Each of these screens includes an inner wooden frame ID preferably of square or rectangular form having side bars I I connected by end cross bars I 2, the side bars I I being shown as somewhat higher than the cross bars I2 and as having a strip I3 of felt applied thereto. At one end of the screen the ends of the side bars I I are extended, as indicated at I4, to connect with an outer screen frame (not shown) and provide the usual .fthroughs and overs passages which extend vertically through the stack of screen frames.

The area defined by the inner frame of the screen is divided by a central longitudinal wooden bar I5 which connects the central parts of the end cross bars I2 and the two areas provided by this central longitudinal wooden bar I5 are in turn divided by a pair of central cross bars I6 each connecting the central part of the central longitudinal bar I5 with the corresponding side bar II. The upper faces of these central bars i5, I6 are preferably coplanar with the upper faces of the end cross bars and with steps l8 provided in the longitudinal bars II, the screening cloth 20 being applied to these coplanar faces and being secured to the end cross bars I2 and the steps I8 of the longitudinal bars II in any suitable manner. This screening cloth 20 can be of fabric, such as bolting silk, or can be of woven metal wire screening.

A rectangular grid 2| of coarse woven metal wire is shown as applied to the underside of the inner frame of the screen, the edges of this grid being shown as recessed into the longitudinal cross bars I I I2 and as engaging the under faces of the central bars I5, I6. This wire grid forms a cleaner carrier and can be secured to the inner frame in any suitable manner. In the practice of the invention standard hardware galvanized grade of square mesh woven wire can be employed, such grade being very low in cost as compared with the heavier grades now required. It will be .seen that the screen frame bars I I and I2; central bars I5 and I6; screening cloth 20 and cleaner carrier 2| provide enclosed rectangular compartments 22 which in the screen shown are four in number.

The screen cleaners 23 in each of these compartments 22 can be of any form but each is shown as being in the form of one or more rubber balls. However, as illustrated in the said Pickard application these cleaners can be merely strips of cotten belt or can be in the form of so-called figure 8 cleaners, each comprising a leather figure 8 body having bristles projecting upwardly from its extremities. The screen cleaners can i also be in the form of cylindrical rubber blocks.

The principal feature of the present invention resides in the provision of a structure or grid which divides the compartments into subcompartments for the screen cleaners and carrying pads which support and engage the screening cloth 20 near the center of each of the compartments 22, the screen cleaners continuously striking and bodily displacing this structure or grid and having their activity'greatly increased and agitating the pads to continuously jar the screening cloth through motion derived from the cleaners. By providing such a supporting structure which subdivides each compartment 22 into subcompartments the travel of each cleaner is restricted thereby to increase the effectiveness of each cleaner both in its direct action against th e screening cloth and also in jarring the supporting structure and the pads carried thereby. Further, the supporting structure is so constructed that it does not blind or block off any part of the screening cloth 2!] thereby to render the full area of the cloth over the compartments 22 available for screening purposes.

In the form of the invention shown in Figs. 1-4, this supporting structure or grid, indicated generally at 25, for the pads is in the form of a pair of sheet metal strips '26 and 28 arranged ,to form a rectangular cross with the ends of the arms thereof secured to the four wood bars place and jar the structure and this jarring movement is transmitted through the rubber pads 46 to the screening cloth so as to effect a jarring thereof, this being effective in combination with the accelerated activity of the screen cleaners, as previously stated, to prevent blinding with difiicult materials, such as sulfur, and to increase the efficienc and capacity of the screen with normal materials.

It will further be noted that the form of the invention shown in Figs. and 6 provides substantially greater screening area than the form of the invention shown in Figs. 1-4 and also provides substantially greater screening area than the usual Brantingham type of sieve shown. Thus in Figs. 1-4, and in the usual Brantingham type of sieve, a substantial area of the screening cloth is blocked off by the wooden central bars I5, l6. In Figs. 5 and 6 these central bars are eliminated and as the strips or bars 4|, 42 of the structure 40 are spaced a substantial distance from the screen cloth, the full area of this screen cloth, as defined by the frame bars II and I2, is useful.

From the foregoing it will be seen that the present invention provides a simple and inexpensive form of screen which will handle materials not heretofore capable of commercial separation on a gyratory sifter and which has increased efficiency and capacity for normal materials as compared with screens of similar size now in general use,

I claim as my invention:

1. A screen for gyratory sifters gyrated in a horizontal plane to described circles, comprising, in combination, a rectangular screen frame having opposed generally parallel side walls, a generally horizontal screening cloth arranged on said frame, a generally horizontal foraminous cleaner carrier arranged on said frame below said screening cloth and forming with said frame and said screening cloth an enclosed compartment, a relatively thin laterally flexible strip arranged vertically on edge within said compartment with its upper longitudinal thin edge adjacent said screening cloth and in spaced relation thereto, means connecting the opposite ends of said strip with two of said opposite generally parallel side walls of said frame and in spaced relation with the other generally parallel side walls of said frame to provide two subcompartments in said compartment, a freely movable screen cleaner in each subcompartment and engageable with said screening cloth, said strip being of such thinness as to be bodily displaced by the impacts of said screen cleaners in the normal operation of the sifter, and a flat pad mounted on said strip in spaced relation to said frame and engaging and supporting said screening cloth in said spaced relation to said strip, the striking of said strip by said screen cleaners bodily displacing said strip and said pad thereby to effect jarring of said screening cloth.

2. A screen for gyratory sifters gyrated in a horizontal plane to describe circles, comprising, in combination a rectangular screen frame having opposed generally parallel side walls, a generally horizontal screening cloth arranged on said frame, a generally horizontal foraminous cleaner carrier arranged on said frame below said screening cloth and forming with said frame and said screening cloth an enclosed compartment, a pair of crossed relatively thin laterally flexible strips each arranged vertically on edge within said compartment withits upper longitudinal thin edge adjacent said screening cloth and in spaced relation thereto, means connecting the opposite ends of said strips with the corresponding opposite generally parallel side walls of said frame to provide at least four subcompartments in said compartment, a freely movable screen cleaner in each subcompartment and engageable with said screening cloth, said strips being of such thinness as to be bodily displaced by the impacts of said screen cleaners in the normal opera-- tion of the sifter, and a flat pad mounted on at least one of said strips in spaced relation to said frame and engaging and supporting said screening cloth in said spaced relation to said strips, the striking of said strips by said screen cleaners bodily displacing said strips and said pad thereby to effect jarring of said screening cloth.

3. A screen for gyratory sifters gyrated in a horizontal plane to describe circles, comprising, in combination, a rectangular screen frame having opposed generally parallel side walls, a generally horizontal screening cloth arranged on said frame, a generally horizontal foraminous cleaner carrier arranged on said frame below said screening cloth and forming with said frame and said screening cloth an enclosed compartment, a pair of crossed relatively thin laterally flexible strips each arranged vertically on edge within said compartment with its upper longitudinal thin edge adjacent said screening cloth and in spaced relation thereto, means connecting the opposite ends of said strips with the corresponding opposite generally parallel side walls of said frame to provide at least four subcompartments in said compartment, a freely movable screen cleaner in each subcompartment and engageable with said screening cloth, said strips being of such thinness as to be bodily displaced by the impacts of said screen cleaners in the normal operation of the sifter, and a flat pad mounted on the crossed part of said strips in spaced relation to said frame and engaging and supporting said screening cloth in said spaced relation to said strips, the striking of said strips by said screen cleaners bodily displacing said strips and said pad thereby to effect jarring of said screening cloth.

4. A screen for gyratory sifters gyrated in a horizontal plane to describe circles, comprising, in combination, a rectangular screen frame having opposed generally parallel side walls, a generally horizontal screening cloth arranged on said frame, a generally horizontal foraminous cleaner carrier arranged on said frame below said screening cloth and forming with said frame and said screening cloth an enclosed compartment, at least four crossed relatively thin flexible strips each arranged vertically on edge within said compartment with its upper longitudinal thin edge adjacent said screening cloth and in spaced relation thereto, means connecting the opposite ends of said strips with the corresponding opposite generally parallel side walls of said frame to provide at least eight subcompartments in said compartment, a freely movable screen cleaner in each subcompartment and engageable with said screening cloth, said strips being of such thinness as to be bodily displaced by the impacts of said screen cleaners in the normal operation of the sifter, and a fiat pad mounted on each of said strips in spaced relation to said frame and engaging and supporting said screening cloth in said spaced relation to said strips, the striking of said strips by said screen cleaners bodily displacing said strips and said pads thereby to effect jarring of-said screening cloth.

5. A screen for gyratory sifters gyrated in a horizontal plane to describe circles, comprising, in combination, a rectangular screen frame having opposed generally parallel side walls, a generally horizontal screening cloth arranged on said frame, a generally horizontal foraminous cleaner carrier arranged on said frame below said screening cloth and forming with said frame and said screening cloth an enclosed compartment, a multicellular grid member arranged in said compartment and secured at its margins to said frame and dividing said compartment into a multiplicity of subcompartments, the upper side of said grid member being arranged in closely spaced relation to said screening cloth and presenting a relatively small opposing face, a freely movable screen cleaner in each subcompartment and engageable with said screening cloth, the members constituting said grid being of such horizontal thinness as to be bodily displaced by the impacts of said screen cleaners in the normal operation of the sifter, and a multiplicity of spaced pads mounted on said grid and engaging and supporting said screening cloth in said closely spaced relation to said grid,

the striking of said grid by said screen cleaners bodily displacing said grid and said pads thereby to elfect jarring of said screening cloth.

HOWARD H. MOYER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

